Liquid rheostat



R. E. HELLMUND Sept. 2

LI QUID RHEOSTAT Filed June 15. 1921 4g 45 INVENTOR fuaa f/k/mu/u :ATTORNEY Patented Sept. 2, 1924.

UNITED STATES PATENT OFFICE.

RUDOLF E. HELLMUND; OF SWISSVALE, PENNSYLVANIA, ASSIGNOR TO WESTING- HOUSE ELECTRIC & MANUFACTURING COMPANY, A CO'RYORATION OF PENNSYL- VANIA.

LIQUID RHEOSTAT.

Application filed June 15, 1921. Serial No. 477,688.

To all whom it may concern:

Be it known that I, RUDoLr E. HELL- MUND, a citizen of the United States, and a resident of Swissvale, in the county of Allegheny and State of Pennsylvania, have invented a new and useful Improvement in Liquid Rheostats, of which the following a specification.

My invention relates to liquid rheostats and it has particular relation to rheostats that are employed in railway motor-control systems. r

One object or my invention is to provid a liquid rheostat in which the electrodes are raised and lowered in the liquid by poweractuated means.

Another object of my invention is to provide means for so actuating a plurality of electrodes that each electrode may be raised or lowered in a rheostat regardless of the position of the other electrodes.

Another object of my invention is to pro vide means for actuating one or more electrodes slowly in one direction and rapidly in another direction, to vary the resistance of an electrical circuit.

Heretofore, rheostats have been provided with electrodes mechanically connected, one with another, and actuated by some mechanical means. However, it is believed that no liquid rheostat has been designed wherein the operation of each of. the electrodes is independent of that of the others and wherein the speed at which each electrode is low ered is independent of the speed at which the electrode is raised from the liquid.

Briefly speaking, my invention consists in providing a plurality of electrodes that are independently actuated and have diiierent speeds for inserting or reducing the resistance in an electrical circuit.

For a better understanding of my invention, reference may be made to the accompanying drawing,

Figure 1 of which is a view, partly in sec tion and partly in end elevation, of a liquid rheostat embodying my invention.

Fig. 2 is a view, partly in section and partly in side elevation, of a modified form of liquid rheostat embodying my invention;

Fig. 3 is a cross-sectional view taken along the'line III-III of Fig. 2; and

Fig. 4 is a diagrammatic View of a control system embodying my invention.

Referring particularly to Fig. 1, a liquid rheostat lcomprises a tank or compartment 2, containing an electrolyte 3, in which fluid a plurality of electrodes or plates 1 may be immersed.

.Each of the electrodes -1- is mechanically connected to a corresponding arm or lever 5, which is pivotally mounted, at an intermediate point. upon a supporting member 6 by means of a pin T. The arm 5 is actuated by an electro-pneumatic device 8, having a piston 9 to which the arm 5 is mechanically connected by a rod or link 10 and a plurality of pins 11.

The electro-pneumatic device 8 comprises a hollow cylinder 12 in which a resilient member or spring 13 biases the piston 9 toward the position that is shown in the drawing. Fluid pressure is supplied to the cylinder 12 through a pipe 14 from a valve mechanism 15 lnwing an exhaust valve plug 16 and an inlet valve plug 17, which are actuated by an armature member or plunger 18. A resilient member or spring 19 tends to bias the plunger 18 to its upper or off position, as shown in the drawing.

A solenoid 20 is employed to actuate the armature member 18, in a downward direc tion, to open inlet port 17a and close exhaust port 16a, thereby permitting air to enter from a pipe 21 through a chamber 22 and pipe 14L into the hollow cylinder 12.

Each electrode is electrically connected to a suitable contact terminal 23 by a conductor 241.

The operation olthe rheostat 1 is begun by energizing the solenoid 20 of the electropneumatic device S,-thereby closing the eX- haust port lGa. and opening the inlet port 170, thus permitting air to be supplied from a source (not shown) through a pipe 21, chamber 22 and pipe l t to the hollow cylinder 12. Fluid pressure upon the piston 9 causes it to be actuated in an upward direction, thereby causing the rod 10 to so turn the arm that the electrode at will be lowered into the electrolyte 7 The speed of this operation is dependent upon the relative values of the air pressure that is applied to the piston 9 and the opposing force ot'resilient member or spring 13.

The electrode- 4L may be raised from the electrolyte by (lo-energizing the actuating coil 20 of the electro-pneumatic device 8, thereby permitting the spring 19 to actuate the armature member 18 to close the inlet valve 17 and to open the exhaust valve 16, thus releasing air from the hollow cylinder 12.

The resilient member 13 will thereupon rapidly actuate the piston 9 in a downward direction, thereby causing the electrode 4 to be raised from the electrolyte 3.

The energization of each actuating coil 20 may be made independent of any other actuating coil or certain of the actuating coils 20 may be connected in either series or parallel relation to produce simultaneous operation of two or more electrodes 4.

Referring to the modified form of liquid rheostat shown in Figs. 2, 3 and 4 of the drawing, corresponding parts have been given like numbers. A plurality of electrodes 28 are pivotally mounted upon a shaft 29 by means of a plurality of arms 30. A lever 31, which is provided with a weight 32 at its one end, is secured at its other end to the shaft 29 by a pin 33. The weight 32 biases the electrodes 28 to their upper or off position, which is that shown in Figs.

' 2 and 3 of the drawing.

A drum 34, constituting a portion of a main controller 34a, is mounted upon the shaft 29 and is provided with a contact segment 35, which is adapted to engage a plurality of control fingers 36, 37 and 38. The shaft 29 is actuated by a motor 39, to which it is mechanically connected by means of a clutch 40 and a worm-gear mechanism 41. The worm-gear mechanism 41 com prises the customary worm wheel 42 and worm 43.

The clutch 40 comprises an armature member 44 which is slidably mounted longitudinally upon the shaft 29 and rotatably locked thereon and a magnetizable longitudinally stationary or disc member 45, which is mechanically connected to the wornrwheel 42. The member 45 is provided with a solenoid 46, which may be energized through a plurality of slip-rings 47.

Referring to Fig. 4 of the drawing, the motor 39 is provided with an armature 48 and a shunt field-magnet winding 49 which may be energized from a source of electrical energy, such, for example, as a battery 50.

f The operation of the motor 39 is governed by a master controller 52, having an off position and a plurality of operating positions at and b.

The operation of the liquid rheostat shown in Figs. 2 and 3 of the drawing, is begun by actuating the master controller 52 from its off position to position (1 thereby establishing a circuit from the battery through conductor 53, one of the slip-rings 47, solenoid 46, the other slip-ring 47 and control fingers 54 and 54, which are bridged by the contact segment 55 of the master controller 52, to the opposite terminal of the battery 50.

The energization of the solenoid 46 of the clutch 4O magnetizes the stationary member 45 which actuates the slidably mounted armature member 44 until it engages the member 45.

A second circuit is established from the positive terminal of the battery 50 through control fingers 37 and 38, which are bridged by contact segment 35 of the main controller 34a, control fingers 59 and 60 of the master controller 52, which are bridged by contact segment (51, and armature 48 and shunt field-magnet winding 49, which are connected in parallel relation, to the negative terminal of the battery 50.

The energization of the arn'iature 48 and shunt field-magnet winding 49 of the motor 39 causes the motor to drive the worm 43, worm wheel 42 and clutch 40 and, hence, the shaft 29, in a direction whereby the plates 28 are lowered into the electrolyte 3. When the main controller 34a has traveled to position I), control finger 37 no longer ei'igages contact segment 35, thereby breaking the circuit comprising the motor 39 and thus stopping the downward movementof the electrodes 28 at an intermediate position in the liquid rheostat.

To lower the electrodes 28 deeper into the electrolyte 3, the master controller 52 must be actuated to position 5, thereby establishing a circuit from the positive terminal of the battery 50 through control fingers 36 and 38, which are bridged by contact segment 35 of the main controller 34a, control fingers 62 and 60, which are bridged by contact segment 61 of the master controller 52, and parallel-connected armature 48 and shunt field-magnet winding 49 of the motor 39 to the negative terminal of the battery 50.

When the main controller 34 has been actuated to position 0, control fingers 36, 37 and 38 no longer engage the contact segment 35, thereby (lo-energizing the motor 39, thus causing the downward movement of the electrodes 28 to cease.

The electrodes 28 may be readily elevated from the electrolyte 3 by actuating the master controller 52 to its off position, thereby interrupting the circuit comprising the con trol finger 54 and the contact segment of the master controller 52 and the solenoid 46 of the clutch 40.

When the armature member 44 is released from engagement with the longitudinally stationary member 45, the weight 32 at the outer end of the arm 31 automatically elevates the electrodes 28 from the electrolyte.

The object of rapidly removing the electrodes from the electrolyte is to prevent the undesirable loss of time in inserting resist ance in an electrical circuit that would occur, if the electrolyte were discharged from the tank through orifices.

WVhile I have shown myinvention in a preferred form, it is apparent that minor modifications in the arrangement of the parts and in structural details may be made without departing from the spirit of my invention. I desire, therefore, to be limited only by the scope of the appended claims.

I claim as my invention:

1. In a liquid rheostat, the combination With a tank, of an electrode, power-actuated means for lowering said electrode in said tank and automatic means for raisin said electrode in said tank.

2. In a liquid rheostat, the combination With a tank, of an electrode, means for actuating said electrode in one direct'on in said tank and means in part independent of said first means for actuating said electrode in another direction.

3. In a liquid rheostat, the combination with a compartment capable of holding a liquid, of an electrode, electro-pneumatic means for actuating said electrode in one direction in said tank, and resilient means for actuating said electrode in another direction in said tank.

4. In a liquid rheostat, the combinat on with a compartment capable of holding a liquid, of an electrode, means for actuating said electrode in one direction in said tank and means for actuating said electrode more rapidly in another direction in said tank.

5. In a liquid rheostat, the combination with a compartment, of a plurality of electrodes and means comprising a plurality of electrical devices for separately actuating said electrodes.

6. In a liquid rheostat, the combinat'on with a tank, of an electrode, means comprising a motor for actuating said electrode in one direction and means independent of said motor for actuating said electrode in another direction. I

7. In a liquid rheostat, the combination With a tank, of an electrode, a shaft for actuating said electrode, a motor for driving said shaft, a clutch for mechanically connecting said motor to said shaft and means independent of said motor for actuating said electrode upon the release of said clutch.

8. In a liquid rheostat, the combination with a tank, of a shaft, an electrode mounted upon said shaft, a motor for actuating said shaft, a clutch for mechanically con necting said motor to said shaft, and means comprising a weight for actuating said shaft upon said clutch being released.

9. In a liquld rheostat, the combination with a tank, of an electrode, power-actuated means for lowering said electrode in said tank and means for rendering said actuating means inoperative upon said electrode occupying a predetermined position.

10. In a liquid rheostat, the combination with a tank, of an electrode, power-actuated means for lowering said electrode in said tank, means for rendering said actuating means inope 'ative upon said electrode occupying a predetermined position and means for rapidly raising said electrode.

In testimony whereof, I have hereunto subscribed my name this 3rd day of June 1921. I

RUDOLF E. HELLMUND. 

